Nope, he didn't witness Desmond using this power in his previous life. As for the reason why Desmond didn't use it, it's because the faction who developed this power were allies of the humanity in his previous life and they wouldn't sabotage their reputation by having their members openly use this power. Plus from what is mentioned in the novel, this power is still in the experimental phase.

Not aliens per se but more like monsters. If you want I can give you the entire whole ass history as to how they came into existence but if I have to but it bluntly, they are humans who had been turned into monsters and there are also humans capable of using the power of their God also called Demon God.

I don't know about you guys but that Sian is really getting on my nerves.

I guess it might be because if they added every little thing Ghislain did in the novel(yeah, he did a lot of territory development in the novel) then we wouldn't have as many fight scenes we had this early on. Though to be honest, I can't see what they plan to do since they offed Woroka quite early even though he had a major role to play in one of the later arc.

In the novel, the MC receives his steed which he later named as Kong(also known as Black King) from the Northern Tribe. In the manhwa, they pretty much rushed that arc in 2 chapters. But basically what happens is that due to the famine brought on by the drought, a few tribes coalesce under Kutsu and attacks Perdium for food. Ghislain comes to their rescue and kills Kutsu earning himself the moniker 'The Red Demon' among the tribals. Not satisfied with always on the defending side, this time Ghislain launches an attack on the Barbarians destroying several more tribes. The remaining tribes form an alliance under Woroka to fend off against Ghislain's attack. Woroka didn't want to fight against Ghislain since the latter had defeated Kutsu who was on the same level as Woroka in terms of strength. They form a non-aggression deal lasting for upto 5 years where Ghislain will provide them with food while Woroka supplies with them horses instead. The barbarians were specialized in rearing horses and Ghislain wanted to form horse-riding archery unit with the Elven slaves he received as support from Branford. Ghislain rounds about around 2000 horses from his initial attacks and forces Woroka to send a fixed number of horses every year as part of the deal. His steed called as Kong in the novel was the unruliest of the horses sent to them and basically on Ghislain manages to tame him making him his signature steed.

Uh...I was just explaining that Zhou Yi-fan didn't pick a fight but was rather picked on. As for why I used spoiler tag, well.....I just thought it would not be good if someone who didn't want any spoilers read the comment though they weren't much of a spoilers to begin with but I kept it anyway.

Zhou Yi-fan didn't pick a fight with those Saint Rank people arbitrarily. From the very start, Zhou Yi-fan was a rebellious leader who never caved into their demands. This is also what made him to be the leader of Emperors since only he was brave enough to go against the Saint Domain people. Those Saints also didn't mess with Zhou Yi-fan more than necessary since there wasn't enough incentive for them to take a huge loss that would result in taking down the Demonic Emperor. But things changed when Zhou Yi-fan acquired one of the most coveted treasures, the Nine Serenities Inheritance and they basically ensnared his disciple to turn on him.

Obviously Not. Unlike what Decimating Dragon Ancestor said, the situation surrounding the Heavenly Sovereign and the war between him and other Sovereigns and Sacred Beasts is a lot more complex. I won't go into the details since that will just take more time but in a nutshell, Zhou Fan is not the reincarnation of Zhou Yi-fan but Zhou Yi-fan himself is the 33rd reincarnation of the Heavenly Sovereign's younger brother. When Qincheng was about to die, Zhou Fan unconsciously transferred the Sovereign Path within him to Qincheng allowing her soul to be reborn in the Sacred Domain. Later on when Zhou Fan meets her in the Sacred Domain, she completely forgets about but is still drawn to him instinctively. This time around, Zhou Fan was the one who pursues Qincheng relentlessly and it is only at the end after all the war is over that Qincheng is shown to have regained her memories and live together.

If you mean his children by 'they', then yeah, they know he is alive from the start. Since this was a fight involving all of the Sacred Beasts, they would have been roped into the fight regardless of Zhou Fan's inheritance so Zhou Fan saw no reason to hide it from them.
If you mean about Qincheng and others like Luo Clan when saying 'they', then it will be quite a long time before they realized he is still alive but even then, unfortunately, Qincheng doesn't get to meet him in truest sense while Luo clan doesn't get to see him at all. After that some shit happens and Zhou Fan is once again presumed dead.

Spoiler: What he said is partially true. Qincheng doesn't actually become cripple but loses her mind over Zhou Fan's death. She basically loses all reasoning living like a mute, always needing to be taken care of. Even after reuniting with Zhou Fan, she could only feel his presence instinctively and doesn't regain her sanity even until "death".

The difference from his past life is that he is becoming a lone wolf for the sake of others unlike in his past life where he was all alone because he cared for no one. Though, this choice was also wrong since it only caused greater suffering on others.

His lonewolf phase is going to last quite a bit. Apart from his children, Gu Santong and Qaio'er, he doesn't let anyone get close to his heart.

Nah, he is telling the truth but only the truth he knows. The actual circumstances are more complicated than this and this Dragon is simply in the dark about such matters.

Obviously, Zhou Fan wins but in a way, the battle itself was won by the Heavenly Sovereign. I will write how the battle went on but am not including the underlying past events that took place to reach the current battle as that would make the message too long.
The Heavenly Sovereign was the older brother of the Zhou Fan's very first life(Zhou Yi-fan the Demonic Emperor was his 33rd reincarnation I think).
As said by the Decimating Dragon Ancestor, the Heavenly Sovereign was an arrogant being who wanted become the absolute ruler of the world capable deciding each and every being's fate. But as already said in the manhwa, he too is still a being bound by the laws of the world and can't be a ruler in truest sense.
The closest clue Heavenly Sovereign has in order to cross the Sovereign Realm is to use the Nine Serenities cultivation method and combine all the powers of other Sovereign paths and Sacred Beasts.
Zhou Fan manages to inherit all the Sovereign Paths but the Heavenly Sovereign uses his Divine Eye to extract those paths from him. After he was done with that, he tried to kill Zhou Fan but Shuanger and Baili Yuyu rescue him while sacrificing their lives.
The Sovereign had now reached the Supreme Realm he had long wanted to reach and he kills of the Lou clan who had come to rescue Zhou Fan and the Sacred Beasts were stopped by the Sword Sovereign and as they watched Heavenly Sovereign reach the next stage, they too lost hope in winning the battle.
However, they were rescued by the Sword Sovereign who betrayed the Heavenly Sovereign and dies.
In the mean time, Zhou Fan who hovering over life and death, meets the soul of Nine Serenities who comes to know of the entire past and as he watched all of his previous lives, his insight of Dao increases allowing him to get closer to the world with the help of Self Art he got from his master.
Basically, with the help of True Self Art, Zhou Fan manages to reach the Heaven and Earth Realm which is the actual state where one can control the entire world, not the Supreme Realm.
Zhou Fan then revives all of Lou clan who died in the battle and erased himself from everyone's memories and disappear to a shed where he forcefully brought the Heavenly Sovereign.
And although it wasn't explicitly state in the novel, Zhou Fan likely killed or trapped the Heavenly Sovereign for all of eternity in that shack.
The novel ends with Zhou Fan taking two poor sisters as his disciples who were the reincarnations of Shuanger and Baili Yuyu and takes them to his home where Qincheng was waiting for him.
It's been nearly 3 years since I finished the novel so I might be wrong about a few minor details so if anyone finds them then you are free to correct me.

Well since I was answering his question, I didn't find the need to add a spoiler tag to the answer itself. I only kept the spoiler tag to the part of the comment that isn't actually related to the answer he was seeking.

No, they are all allies to the end though Zhou Fan kind of screws them over in between. Though Zhou Fan doesn't get to have a talk with due to his immediate battle with Heavenly Sovereign.

No, they are all allies and don't actually fight. Even though Zhou Fan kind of screws them over but it wasn't a full fledged grudge between the two. Zhou Fan doesn't even get the chance to have a conversation with them before he is forced to fight the Heavenly Sovereign.